Capsule for non-ferrous metal collection and method of collecting non-ferrous metal

ABSTRACT

Provided are: a capsule for non-ferrous metal collection that can collect a non-ferrous metal; and a method for collecting a non-ferrous metal using same. The capsule for non-ferrous metal collection comprises capsule contents and a covering section covering the capsule contents, and collects a non-ferrous metal within the capsule for non-ferrous metal collection by means of the capsule for non-ferrous metal collection being immersed in a solution containing a non-ferrous metal.

TECHNICAL FIELD

The present invention relates to a capsule which can collect anon-ferrous metal, and a method of collecting a non-ferrous metal usingthe same.

BACKGROUND ART

Non-ferrous metals other than steel material (iron and alloy containingmainly iron) are becoming highly useful in industry, and an amount of anon-ferrous metal to be used is increasing. In order to avoid resourcedepletion of the non-ferrous metals, recycle technique which effectivelyutilizes non-ferrous metals contained in wastes such as home electricappliances is becoming highly important. For example, rare metal or rarenoble metal is recovered from parts of wasted mobile phones, personalcomputers, automobiles and the like, which is sometimes called urbanmines and intensely studied.

For recovering rare metal or rare noble metal, a recovery method using achemical reaction, a recovery method using solvent extraction, and thelike have been conventionally proposed. For example, JP-A 2010-150569discloses a method for producing a platinum group element metal powder,comprising chlorinating waste material containing a platinum groupelement in a molten salt bath to form a metal chloride, and thensubjecting the resulting metal chloride to reduction treatment to obtainmetal powder having high purity. In the method, chlorine gas is blowninto the molten salt bath and reacted at a temperature of 300 to 1000°C., whereby a chloride of a metal to be recovered is formed.Accordingly, a recovery method using a chemical reaction has a problemthat consumption of a large amount of energy is accompanied. Further,there is also a problem that the cost of constructing a recovery systemis necessary.

As the recovery method using solvent extraction, JP-A 2007-270250discloses, as a method of selectively recovering a platinum group metalfrom an aqueous solution, a procedure of back-extracting palladium withan aqueous ammonia solution, and crystallizing palladium from thepalladium-containing aqueous ammonia solution. The solvent extractionmethod has an advantage that, even when a concentration of a metalcomponent is low, the metal component can be recovered. On the otherhand, it is necessary to use a large amount of various solvents such asan organic solvent. For this reason, there is a problem that a largeamount of waste solvent is generated and an environmental load is great.

JP-A 2008-127604 describes use of a biological membrane, such as an eggshell membrane, in a method of recovering a noble metal. The recoverymethod, however, needs an electric reduction recovery method, such as agold electrolysis method, and has a different configuration from that ofthe method of the present invention.

OBJECT OF THE INVENTION

As a method of recovering a useful rare metal or rare noble metal,various methods have been studied as described above. However, themethods have some problems in respect of energy consumption orenvironmental load. As other methods, recovery methods using, forexample, an adsorbent or a microorganism are studied, but the methodsalso have a problem that a recovery rate is low. An object of thepresent invention is to solve such conventional problems.

SUMMARY OF THE INVENTION

That is, the present invention provides a capsule which can collect anon-ferrous metal easily and well, and a method of collecting anon-ferrous metal using the same.

The present invention provides a capsule for collecting a non-ferrousmetal comprising a capsule content and a shell covering the capsulecontent, wherein the capsule is immersed in a solution containing thenon-ferrous metal to collect the non-ferrous metal in the capsule, andthe aforementioned problems are thus solved.

It is more preferable that the capsule content comprises one or morebacteria selected from the group consisting of Geobacter bacteria,Desulfomonas bacteria, Desulfuromusa bacteria, Pelobacter bacteria,Shewanella bacteria, Ferrimonas bacteria, Aeromonas bacteria,Sulfurospirillum bacteria, Wolinella bacteria, Desulfovibrio bacteria,Geothrix bacteria, Deferribacter bacteria, Geovibrio bacteria,Pyrobaculum bacteria, Thermotogae bacteria, Archaeoglobus bacteria,Pyrococcus bacteria and Pyrodictium bacteria.

In addition, it is more preferable that the capsule content comprisesShewanella bacteria.

In addition, it is more preferable that the capsule content comprisesShewanella oneidensis or Shewanella algae.

In addition, it is more preferable that the non-ferrous metal to becollected is one or more selected from the group consisting of a raremetal and a rare noble metal.

In addition, it is more preferable that the non-ferrous metal to becollected is palladium, platinum, rhodium, gold, silver, indium, galliumor a rare earth element.

It is more preferable that the capsule content further comprises atleast one selected from the group consisting of an electron donatingcomponent, an electron accepting component and a liquid culture medium.

In addition, it is more preferable that the capsule for collecting anon-ferrous metal is a seamless capsule.

It is more preferable that the shell is obtained by curing a shellformation composition comprising a photocurable component and a shellpermeation aid.

It is more preferable that the photocurable component is one or moreselected from the group consisting of an acrylate-based oligomer, anunsaturated polyester-based oligomer, a polyene thiol-based oligomer, acinnamic acid-based oligomer, an epoxy-based oligomer, a vinylether-based oligomer and an unsaturated polyamide-based oligomer, andthe shell permeation aid is one or more selected from the groupconsisting of alginic acid, polyvinyl alcohol, agar, carrageenan, gellangum, pectin, starch, a starch derivative, dextrin, cellulose andprotein.

Examples of one aspect of the capsule for collecting a non-ferrous metalinclude an aspect in which the capsule content comprises an oily portioncontaining Shewanella bacteria. It is more preferable that this capsulefor collecting a non-ferrous metal is obtained by extruding an oilycomposition comprising Shewanella bacteria from a first nozzle, andextruding a shell formation composition from a second nozzlesimultaneously into a carrier fluid, wherein the first nozzle and thesecond nozzle are concentrically arranged with sequentially increasedradiuses in which the first nozzle is present innermost and the secondnozzle is present outermost, and then curing the shell formationcomposition with light irradiation.

Examples of another aspect of the capsule for collecting a non-ferrousmetal include an aspect in which the capsule comprises an intermediatelayer portion containing an oily substance, and a hydrophilic portioncontaining Shewanella bacteria, wherein the intermediate layer portionis in layer structure at the time of preparing a capsule. It is morepreferable that the capsule for collecting a non-ferrous metal isobtained by extruding a hydrophilic composition comprising Shewanellabacteria from a first nozzle, extruding an oily composition from asecond nozzle and extruding a shell formation composition from a thirdnozzle simultaneously into a carrier fluid, wherein the first nozzle,the third nozzle and the third nozzle are concentrically arranged withsequentially increased radiuses in which the first nozzle is presentinnermost and the second nozzle is present outermost, and then curingthe shell formation composition with light irradiation.

Further, the present invention also provides a method of collecting anon-ferrous metal, including:

an immersion step of immersing the capsule for collecting a non-ferrousmetal in a solution containing a non-ferrous metal, and

a separation step of separating the capsule for collecting a non-ferrousmetal immersed in the immersing step.

Herein, it is preferable that the non-ferrous metal to be collected isone or more selected from the group consisting of a rare metal and arare noble metal. It is more preferable that the non-ferrous metal to becollected is palladium, platinum, rhodium, gold, silver, indium, galliumor a rare earth element.

ADVANTAGES OF THE INVENTION

The capsule for collecting a non-ferrous metal of the present inventionhas an advantage that a non-ferrous metal can be easily collected by asimple operation of immersion in a solution containing a non-ferrousmetal for a given time. In the collection of a non-ferrous metal, anon-ferrous metal can be effectively concentrated and collected, even inthe case where an amount of a non-ferrous metal contained is very small.

In collection of a non-ferrous metal using the capsule for collecting anon-ferrous metal of the present invention, a non-ferrous metal can becollected without accompanying consumption of a large amount of energylike a method using chemical reaction. There is also an advantage that alarge amount of waste solvent is not accompanied like a solventextraction method, and the load on the environment is small. Further, inthe present invention, since a non-ferrous metal can be collected by asimple operation of immersing the capsule for collecting a non-ferrousmetal in a solution for a given period, and, thereafter, taking out thecapsule by a means such as filtration, there is an advantage that thecollection can be simply implemented without accompanying the large costof facility investment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing one example of a preferableembodiment of the capsule for collecting a non-ferrous metal of thepresent invention, and is a schematic view showing a capsule forcollecting a non-ferrous metal having a two-layered structureimmediately after manufacturing.

FIG. 2 is a schematic view showing another example of a preferableembodiment of the capsule for collecting a non-ferrous metal of thepresent invention, and is a schematic view showing a capsule forcollecting a non-ferrous metal having a three-layered structureimmediately after manufacturing.

FIG. 3 is an outline view showing a method for manufacturing the capsulefor collecting a non-ferrous metal of the present invention, having atwo-layered structure, shown in FIG. 1.

FIG. 4 is a graph chart showing changes in Pd (II) ion concentration inan aqueous solution in Example 3 and Reference Comparative Example.

FIG. 5 shows photographs of the capsules for collecting a non-ferrousmetal before a solution immersion operation (after culturing operation,before solution immersion) and the capsules for collecting a non-ferrousmetal taken out after 24 hours from solution immersion, used in Example4.

FIG. 6 is a graph chart showing changes in indium concentration in anaqueous solution in Example 5 and Comparative Test.

FIG. 7 is a graph chart showing changes in gold concentration in an ICchip percolate in Example 6 and Comparative Test.

FIG. 8 is a graph chart showing changes in platinum (IV) concentrationin an aqueous solution in Example 7 and Comparative Test.

FIG. 9 is a graph chart showing changes in gallium (III) concentrationin an aqueous solution in Example 8 and Comparative Test.

FIG. 10 is a graph chart showing changes in rhodium (III) concentrationin an aqueous solution in Example 9 and Comparative Test.

FIG. 11 is a graph chart showing changes in dysprosium (III)concentration in an aqueous solution in Example 10 and Comparative Test.

DETAILED DESCRIPTION OF THE INVENTION Capsule for Collecting Non-FerrousMetal and Method for Manufacturing the Same

The capsule for collecting a non-ferrous metal of the present inventionis composed of a capsule content, and a shell covering the capsulecontent. The capsule for collecting a non-ferrous metal is characterizedin that a non-ferrous metal can be collected into the capsule by asimple operation of immersing the capsule in a solution containing anon-ferrous metal. In the present description, it is intended that theterm “collection” also includes the meaning “recovery”, and the term“collecting a non-ferrous metal” also includes “recovering a non-ferrousmetal”.

In the present description, the “non-ferrous metal” means a metal exceptfor iron and an alloy containing mainly iron. Examples of thenon-ferrous metal to be collected in the present invention include arare metal and a rare noble metal.

Herein, the rare metal means a metal other than a base metal (alsocalled common metal or major metal) such as iron, copper, zinc, andaluminum, which is a metal not belonging to a noble metal such as goldand silver being a non-ferrous metal utilized in industry. Specificexamples of the rare metal include lithium, beryllium, titanium,vanadium, chromium, manganese, cobalt, nickel, gallium, germanium,selenium, rubidium, strontium, zirconium, niobium, molybdenum, indium,antimony, tellurium, cesium, barium, hafnium, tantalum, tungsten,rhenium, thallium, bismuth and a rare earth element. Examples of therare earth element include scandium, yttrium, lanthanum, cerium,praseodymium, neodymium, promethium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.In addition, the rare metal includes palladium, platinum and the like,and, in the present description, it is intended that palladium andplatinum are included in the rare noble metal.

The rare noble metal means a metal, particularly, having a small amountof deposit, and excellent in corrosion resistance, among metals of Group8 to Group 11 in the periodic table of chemical elements. Examples ofthe rare noble metal include gold, silver, platinum, palladium, rhodium,iridium, ruthenium and osmium.

More preferable examples of the metal to be collected by the capsule forcollecting a non-ferrous metal of the present invention includepalladium, platinum, rhodium, gold, silver, indium, gallium or a rareearth element.

The capsule for collecting a non-ferrous metal of the present inventionis constructed of a capsule content and a shell covering the capsulecontent. Each constituent will be described below.

Capsule Content

It is preferable that the capsule content constituting the capsule forcollecting a non-ferrous metal of the present invention containsbacteria selected from the following group:

Geobacter bacteria (representative species: Geobacter metallireducens:ATCC (American Type Culture Collection) 53774 strain),

Desulfuromonas bacterial (representative species: Desulfuromonaspalmitatis: ATCC 51701 strain),

Desulfuromusa bacteria (representative species: Desulfuromusa kysingii:Desulfuromusa kysingii DSM (Deutsche Sammlung von Mikroorganismen andZellkulturen) 7343 strain),

Pelobacter bacteria (representative species: Pelobacter venetianus: ATCC2394 strain),

Shewanella bacteria (Shewanella algae: ATCC 51181 strain, Shewanellaoneidensis: etc.),

Ferrimonas bacteria (Ferrimonas balearica: DSM 9799 strain),

Aeromonas bacteria (Aeromonas hydrophila: ATCC 15467 strain),

Sulfurospirillum bacteria (representative species: Sulfurospirillumbarnesii: ATCC 700032 strain),

Wolinella bacteria (representative species: Wolinella succinogenes: ATCC29543 strain),

Desulfovibrio bacteria (representative species: Desulfovibriodesulfuricans: ATCC 29577 strain),

Geothrix bacteria (representative species: Geothrix fermentans: ATCC700665 strain),

Deferribacter bacteria (representative species: Deferribacterthermophilus: DSM 14813 strain),

Geovibrio bacteria (representative species: Geovibrio ferrireducens:ATCC 51996 strain),

Pyrobaculum bacteria (representative species: Pyrobaculum islandicum:DSM 4184 strain),

Thermotogae bacteria (representative species: Thermotogae maritima:DSM3109 strain),

Archaeoglobus bacteria (representative species: Archaeoglobus fulgidus:ATCC49558 strain),

Pyrococcus bacteria (representative species: Pyrococcus furiosus ATCC43587 strain), and

Pyrodictium bacteria (representative species: Pyrodictium abyssi:DSM6158 strain).

Since the bacteria are contained in the capsule content of the capsulefor collecting a non-ferrous metal, a non-ferrous metal can be collectedin the capsule well.

In the present invention, it is preferable that the capsule contentcontains Shewanella bacteria. Examples of Shewanella bacteria includeShewanella algae, Shewanella oneidensis, Shewanella algidipiscicola,Shewanella amazonensis, Shewanella baltica, Shewanella benthica,Shewanella colwelliana, Shewanella denitrificans, Shewanella fidelis,Shewanella frigidimarina, Shewanella gelidimarina, Shewanellaglacialipiscicola, Shewanella hafniensis, Shewanella hanedai, Shewanellajaponica, Shewanella loihica, Shewanella marinintestina, Shewanellamorhuae, Shewanella pealeana, Shewanella putrefaciens, Shewanella sp.(KMM 3587) and Shewanella woodyi. It is more preferable that, amongthem, Shewanella algae or Shewanella oneidensis is contained in thecapsule.

The bacteria may preferably be contained in the capsule for collecting anon-ferrous metal in the live state, or may be contained in the capsulefor collecting a non-ferrous metal in the state of dead bacterial cells.For example, Shewanella algae and Shewanella oneidensis arecharacterized in that, even in the state of dead bacterial cells, anon-ferrous metal can be collected well.

In the present invention, the capsule content preferably contains thebacteria in an amount of 0.01 to 30 parts by mass, more preferably in anamount of 0.1 to 20 parts by mass, based on 100 parts by mass of thecapsule content. For example, the bacteria is preferably contained at aratio of 1 cell/capsule to 5×10¹¹ cells/capsule, more preferably at aratio of 1×10³ cells/capsule to 1×10¹¹ cells/capsule, based on thecapsule content (based on one capsule).

In the capsule for collecting a non-ferrous metal of the presentinvention, the bacterium may be contained in the capsule content in thestate of being dispersed in a hydrophilic composition such as an aqueoussolution, or may be contained in the capsule content in the state ofbeing dispersed in an oily composition.

Examples of the hydrophilic composition which can be used for preparingthe capsule content include various aqueous solutions. Examples of theoily composition which can be used for preparing the capsule contentinclude olive oil, jojoba oil, corn oil, rapeseed oil, lard, beeftallow, whale oil, castor oil, soybean oil, rice oil, rice germ oil,coconut oil, palm oil, cacao oil, avocado oil, macadamia nut oil,squalane, mink oil, turtle oil, corn oil, hydrocarbons having 8 to 30carbon atoms, beeswax, carnauba wax, rice wax, lanolin, liquid paraffin,vaseline, fatty acids having 4 to 30 carbon atoms, esters of fatty acidshaving 4 to 30 carbon atoms and sucrose, esters of fatty acids having 4to 30 carbon atoms and glycerol, aliphatic alcohols having 4 to 30carbon atoms, esters of fatty acids having 4 to 30 carbon atoms andaliphatic alcohols having 4 to 30 carbon atoms, and silicone oil. Theseare employed solely or can be used in combination thereof. Among theoily compositions, liquid fat or oil having a viscosity of 200 mPA·s orlower in a temperature range of −30° C. to 60° C. is preferred.

The capsule content may further contain an additional component whichcan keep bacteria good, as necessary. Examples of the additionalcomponent are an electron donating component, an electron acceptingcomponent and various liquid media. When the bacteria are contained inthe capsule content in the state of being dispersed in a hydrophiliccomposition, the following electron donating component or the like maypreferably be contained in the capsule content.

The electron donating component in the present description means acomponent having a nature of donating an electron to the bacteria. Thebacteria can grow well when the capsule content comprises both theelectron donating component and the electron accepting component,because the two components are led to an oxidation-reduction reactionand the bacteria can get growth energy therefrom.

Examples of the electron donating component include:

a carboxylic acid having 1 to 7 carbon atoms and a derivative thereof,for example, formic acid, acetic acid, propionic acid, butyric acid,valeric acid, lactic acid, citric acid, malic acid, tartaric acid,oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid,fumaric acid, maleic acid, and a salt thereof;

an aromatic carboxylic acid having 5 to 10 carbon atoms and a derivativethereof, for example, benzoic acid, phthalic acid, isophthalic acid,terephthalic acid, salicylic acid, gallic acid, mellitic acid, cinnamicacid, and a salt thereof;

an alcohol having 1 to 10 carbon atoms, for example, methanol andethanol;

an unsaturated aromatic compound, for example, toluenephenol; and

hydrogen gas.

Examples of the electron accepting component include a metal ion such asFe (III) ion.

According to the present invention, the electron donating component canbe suitably selected based on the type of bacteria to be used. Forexample, when Shewanella algae is used, a carboxylic acid having 1 to 7carbon atoms or a derivative thereof, such as formic acid and lacticacid or a salt thereof can be preferably used as the electron donatingcomponent. If necessary, as the electron accepting component, Fe (III)ion may also be used. By using the electron accepting component, growthenergy derived from an oxidation-reduction reaction in cells can beobtained well.

When Shewanella oneidensis is employed, the electron donating componentcan preferably be a carboxylic acid having 1 to 7 carbon atoms or aderivative thereof (such as formic acid or a salt thereof).

In case where the bacteria are dispersed in an aqueous composition, itis necessary that oily substance may intervene as an intermediate layerportion between an aqueous composition containing the bacteria and ashell formation composition, when producing the capsule. The oilysubstance can be the same with those explained for the oily compositionabove. Preferable examples of the oily substance which can intervene asthe intermediate layer portion include those having a melting point of60° C. or lower (e.g., olive oil, jojoba oil, corn oil, rapeseed oil,lard, beef tallow, whale oil, castor oil, soybean oil, rice oil, ricegerm oil, coconut oil, palm oil, cacao oil, avocado oil, macadamia nutoil, squalane, mink oil, turtle oil, and corn oil), and sucrose acetateisobutyrate (SAIB) and the like.

When the oily substance intervenes as the intermediate layer portion,the intermediate layer is preferably formed at a weight ratio of 5 to 40parts by mass, and is more preferably formed at a weight ratio of 10 to30 parts by mass, based on 100 parts by mass of the capsule forcollecting a non-ferrous metal.

Shell

In the shell constituting the capsule for collecting a non-ferrous metalof the present invention, a component which can cover the capsulecontent well can be used without particular limitation. In the presentinvention, it is more preferable that the shell is formed from a shellformation composition containing a photocurable component. By formingthe shell using the shell formation composition containing aphotocurable component, there is an advantage that a capsule,particularly, a seamless capsule can be manufactured better and moresimply.

The photocurable component which can be used in the present invention isnot limited as far as it is cured by light irradiation. In the presentinvention, it is more preferable to use an aqueous (hydrophilic)photocurable component as the photocurable component. By forming theshell using the aqueous (hydrophilic) photocurable component, theresulting capsule is excellent in water hydrophilicity of a capsulesurface and shows excellent non-ferrous metal collecting property whenit is immersed in an aqueous solution containing a non-ferrous metal.Examples of the photocurable component include a photopolymerizableoligomer and an addition polymerization product thereof. These may beused alone, or two or more of them may be used in combination.

Examples of the photopolymerizable oligomers are an acrylate-basedoligomer, an unsaturated polyester-based oligomer, a polyene thiol-basedoligomer, a cinnamic acid-based oligomer, an epoxy-based oligomer, avinyl ether-based oligomer, and an unsaturated polyamide-based oligomer.More specifically, an acrylate-based oligomer having at least twoethylenic unsaturated bonds and a hydrophilic group in one molecule, ahigh acid value unsaturated polyester-based oligomer, a high acid valueunsaturated epoxy-based oligomer, an anionic unsaturated acrylicoligomer, an unsaturated polyamide-based oligomer, and the like aresuitably used. Among them, an acrylate-based oligomer having at leasttwo ethylenic unsaturated bonds and a hydrophilic group in one moleculeis preferably used.

Examples of the acrylate-based oligomer having at least two ethylenicunsaturated bonds and a hydrophilic group in one molecule include anoligomer having a photopolymerizable ethylenic unsaturated group on bothterminals of polyalkylene glycol. Examples of the acrylate-basedoligomer include:

(1) polyethylene glycol di(meth)acrylates in which both terminal hydroxygroups of polyethylene glycol having a molecular weight of 400 to 6,000are esterified with 2 moles of (meth)acrylic acid;

(2) polypropylene glycol di(meth)acrylates in which both terminalhydroxy groups of polypropylene glycol having a molecular weight of 200to 4,000 are esterified with 2 moles of (meth)acrylic acid;

(3) an unsaturated polyethylene glycol urethanated product in which bothterminal hydroxy groups of 1 mole of polyethylene glycol having amolecular weight of 400 to 6,000 are urethanated with 2 moles of adiisocyanate compound (tolylene diisocyanate, xylylene diisocyanate,isophorone diisocyanate, or the like) and, further, 2 moles of anunsaturated monohydroxy compound (2-hydroxyethyl (meth)acrylate,2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate,4-hydroxybutyl (meth)acrylate, trimethylolpropane di(meth)acrylate,pentaerythritol tri(meth)acrylate, or the like) is added; and

(4) an unsaturated polypropylene glycol urethanated product in whichboth terminal hydroxy groups of 1 mole of polypropylene glycol having amolecular weight of 200 to 40,000 are urethanated with 2 moles of adiisocyanate compound and, further, 2 moles of an unsaturatedmonohydroxy compound is added.

Examples of the high acid value unsaturated polyester-based oligomerinclude salts of an unsaturated polyester having an acid value of 40 to200, obtained by esterifying polyvalent carboxylic acid having anunsaturated bond, and a polyhydric alcohol.

Examples of the high acid value unsaturated epoxy-based oligomer includean unsaturated epoxy oligomer having an acid value of 40 to 200. Theoligomer is obtained, for examples, by preparing an addition reactionproduct of an epoxy compound and an unsaturated carboxyl compound((meth)acrylic acid or the like), and adding an acid anhydride to ahydroxyl group remaining in the addition reaction product.

Examples of the anionic unsaturated acryl oligomer include an oligomerwhich is derived from at least two (meth)acryl-based monomers of(meth)acrylic acid and (meth)acrylic acid esters, and in which aphotopolymerizable ethylenic unsaturated group is introduced into acopolymer having a carboxyl group, a phosphoric acid group and/or asulfonic acid group.

The unsaturated polyamide-based oligomer is obtained, for example, byadding an addition product of diisocyanate (tolylene diisocyanate,xylylene diisocyanate, or the like) and an ethylenic unsaturated hydroxycompound (2-hydroxyethyl acrylate or the like) to a water-solublepolyamide such as gelatin.

A number average molecular weight of the photopolymerizable oligomers ispreferably 300 to 30,000, and more preferably 500 to 20,000. Herein, thenumber average molecule weight can be measured by a GPC (Gel PermeationChromatography) method.

Among the photocurable components, an acrylate-based oligomer having apolymerizable ethylenic unsaturated group on both terminals ofpolyalkylene glycol can be particularly preferably used.

As the acrylate-based oligomer, commercially available products may beused. Examples of the acrylate-based oligomer which can be used in thepresent invention include an acrylate-based oligomer which is sold fromSanyu Rec Co., Ltd. under a trade name such as RM-6572, RM-6560,RM-6550, RM-6551, and RL-6527; an acrylate-based oligomer which is soldfrom Kansai Paint Co., Ltd. under a trade name such as ENT-1000,ENT-2000, ENT-3400, ENT-4000, ENTG-2000, and ENTG-3800; and anacrylate-based oligomer which is sold from Shin Nakamura Chemical Co.,Ltd. under a trade name such as UA-7100, UA-7000, and UA-W2A.

The photocurable component is preferably contained as a solid content inthe shell formation composition in an amount of 10 to 99% by mass, morepreferably 20 to 90% by mass, and further preferably 40 to 90% by mass.

In the present invention, the shell is preferably formed from acomposition containing the photocurable component, that is, a shellformation composition. The shell formation composition may furthercontain an additive such as a polymerization initiator, aphotosensitizer, a coloring agent, a polymerizable monomer, a shellpermeation aid, and an electric charge adjusting agent, as necessary. Anamount of the additive is preferably 30% by mass or less, and morepreferably 20% by mass or less, based on the mass of the shell formationcomposition, as a solid content.

As the polymerization initiator, a conventionally known polymerizationinitiator suitable for the photocurable component to be used can be usedwithout particular limitation. As the polymerization initiator, aphotopolymerization initiator is suitably used. The photopolymerizationinitiator means a compound which can generate a polymerizationinitiation species by light irradiation and promote a polymerizationreaction or a crosslinking reaction. Examples of the photopolymerizationinitiator include benzoin, acetoin, benzoin methyl ether, benzoin ethylether, benzoin isopropyl ether, benzoin isobutyl ether, benzophenone,benzyl Michler's ketone, xanthone, chlorothioxanthone,isopropylthioxanthone, benzyl dimethyl ketal, naphthol, anthraquinone,hydroxyanthracene, acetophenone diethyl ketal, α-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylphenylpropane, an aromatic iodoniumsalt, an aromatic sulfonium salt, an iodonium salt, a sulfonium salt, atriarylsulfonium salt, a trifluorocarbon sulfonium salt and the like.The polymerization initiator may be used alone, or may be used bycombining two or more kinds. The polymerization initiator is preferablycontained in an amount of 0.001 to 20% by mass, more preferably 0.1 to10% by mass, based on the mass of the shell formation composition, as asolid content. When an amount of the polymerization initiator is lessthan 0.001% by mass, there is a possibility of a problem that apolymerization reaction does not completely progress, a film strengthcannot be provided, or the like and, when an amount exceeds 20% by mass,an initiation reaction excessively progresses, there is a possibility ofa problem that a polymerization reaction does not progress, leading todecrease in a film strength, or the like. In the present invention, itis preferable that the photocurable component and the polymerizationinitiator, particularly the photopolymerization initiator are used byappropriately combining them.

When the shell is formed by curing the photocurable component with avisible light region, it is desirable that a photosensitizer is blendedwith the shell formation composition. Examples of the photosensitizerinclude a ruthenium complex and a porphyrin-based compound. The useamount of the photosensitizer is preferably 0.001 to 5% by mass, andmore preferably 0.01 to 1% by mass, based on the mass of the shellformation composition, as a solid content.

If necessary, to the shell formation composition may be added awater-soluble monomer which is dissolved in an aqueous solvent at 80° C.or lower and has an unsaturated bond (e.g., itaconic acid,N,N′-methylenebisacrylate, hydroxyethyl methacrylate, hydroxypropylmethacrylate, N,N′-methylenebisacrylamide, N-isopropylacrylamide,N-vinylpyrrolidone, acryloylmorpholine, N,N′-dimethylacrylamide, andN-vinylformamide) alone or by combining two or more kinds. By using thewater-soluble monomer, a reaction adversely influencing on apolymerization reaction can be suppressed, and strength of the shell canbe further enhanced. An amount of the water-soluble monomer ispreferably 0.01 to 30% by mass, and more preferably 0.1 to 25% by mass,based on the mass of the shell formation composition, as a solidcontent.

It is more preferable that the shell formation composition contains ashell permeation aid. A shell obtained by curing the shell formationcomposition containing a photocurable component and a shell permeationaid has an advantage that permeability of a non-ferrous metal ion ishigh and, therefore a non-ferrous metal can be collected better.Examples of the shell permeation aid include alginic acid, polyvinylalcohol, agar, carrageenan, gellan gum, pectin, starch, a starchderivative (alkylated starch, etherized starch, and the like), dextrin,cellulose, and protein. The shell permeation aid is preferably containedat a solid content ratio of 1 to 0.1 to 30% by mass, and more preferably0.5 to 30% by mass, based on the shell formation composition.

When the shell permeation aid is contained in the shell formationcomposition, the shell formation composition is cured and then subjectedto a treatment, such as enzyme treatment, alkali treatment or acidtreatment for enhancing permeability of the shell. The treatments cut,degrade or dissolve a part of a polymer forming the shell, therebymaking it possible to improve permeability of the shell.

As another aspect, the shell constituting the capsule for collecting anon-ferrous metal of the present invention can also be formed using theshell formation composition containing a thermosetting component. Thethermosetting component can generally be used by a person skilled in theart. Examples of the thermosetting component include an acrylate-basedoligomer, an unsaturated polyester-based oligomer, a polyene thiol-basedoligomer, a cinnamic acid-based oligomer, an epoxy-based oligomer, avinyl ether-based oligomer, and an unsaturated polyamide-based oligomer,exemplified as the photopolymerizable oligomer.

When the shell is formed from the shell formation composition containingthe thermosetting component, it is preferable that a thermalpolymerization initiator is used together. The thermal polymerizationinitiator is generally used by a person skilled in the art. Specificexamples of the thermal polymerization initiator include an azo compoundsuch as 4,4′-azobis(4-cyanovaleric acid),2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(isobutyronitrile),2,2′-azobis(2-methylbutyronitrile), and dimethyl2,2′-azobis(2-methylpropionate), and a peroxide compound such asdibenzoyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide,di-tert-butyl peroxide and the like. The thermal polymerizationinitiator is preferably contained in an amount of 0.001 to 20% by mass,and more preferably 0.1 to 10% by mass, based on the mass of the shellformation composition, as a solid content.

Also in the case where the shell is formed from the shell formationcomposition containing the thermosetting component, the aforementionedshell permeation aid can be used as described above.

In the capsule for collecting a non-ferrous metal in the presentinvention, the shell can also be formed from the shell formationcomposition containing a thermoplastic resin. Examples of thethermoplastic resin which can be used in formation of the shell includea thermoplastic resin which is generally used by a person skilled in theart, such as a polyolefin resin, for example, a polyethylene resin or apolypropylene resin, a polystyrene resin, an AS resin, an ABS resin, avinyl chloride resin, an acrylic resin, a methacrylic resin, a methyl(meth)acrylate resin, a fluorine resin, a polycarbonate resin, or apolyester resin such as a polyethylene terephthalate resin or apolybutylene terephthalate resin. Also in the case where the shell isformed from the shell formation composition containing the thermoplasticresin, the aforementioned shell permeation aid can be used as describedabove.

The capsule for collecting a non-ferrous metal of the present inventionencloses bacteria or the like therein. By immersing the capsule forcollecting a non-ferrous metal in a solution containing a non-ferrousmetal for a given time, the solution permeates through the shell, andenters the capsule. The bacteria are activated in the capsule, andnon-ferrous metal collection activity is initiated. Thus, a non-ferrousmetal is collected in the capsule. In the capsule for collecting anon-ferrous metal of the present invention, the bacteria are firstactivated by immersion in a solution containing a non-ferrous metal. Forthis reason, there is an advantage from the viewpoint of handling that abacterium can be retained in the better state until immediately beforeimmersion. There is also an advantage that damage of a bacterium atpreservation of the capsule for collecting a non-ferrous metal can bereduced. In the case where the capsule for collecting a non-ferrousmetal is a seamless capsule, there is an advantage that since thecapsule has a spherical structure, an area of contact with a solutioncontaining a non-ferrous metal is increased and, therefore, anon-ferrous metal can be collected better.

In collection of a non-ferrous metal using the capsule for collecting anon-ferrous metal of the present invention, a non-ferrous metal can becollected without accompanying consumption of a large amount of energylike a method using a chemical reaction which is one kind ofconventional methods. In addition, there is an advantage that a largeamount of waste solvent is not accompanied and the load on environmentis also small, in comparison with the conventional solvent extractionmethod which necessitates a large amount of solvent and gives heavy loadon environment. In the present invention, there is another advantagethat collection of the non-ferrous metal can be easily conducted withoutaccompanying large cost of facility investment, because a non-ferrousmetal can be collected by a simple operation of immersing the capsulesfor collecting a non-ferrous metal in a solution for a given period andthe capsules are easily collected by a means such as filtration.

Method of Manufacturing Capsule for Collecting Non-Ferrous Metal

The capsule for collecting a non-ferrous metal of the present inventioncan be manufactured by extruding the shell formation composition and thecapsule content into a carrier fluid, using a concentric double nozzleor a concentric triple nozzle, and then curing the shell formationcomposition with light irradiation.

In this manufacturing method, it is necessary that components whichcontact each other at preparation preferably have a different polarityfrom each other. For example, in a first embodiment shown in FIG. 1, itis preferred that the shell formation composition is hydrophilic and thecapsule content is an oily composition containing Shewanella bacteria orthe like.

FIGS. 1 and 2 show preferable embodiments of the capsule for collectinga non-ferrous metal of the present invention (first and secondembodiments, respectively). With reference to the respective embodiment,the method of manufacturing the capsule for collecting a non-ferrousmetal of the present invention will be described in detail.

Method of Manufacturing Capsule for Collecting Non-Ferrous Metal HavingTwo-Layered Structure (First Embodiment)

A left drawing of FIG. 1 is a schematic view showing the capsule forcollecting a non-ferrous metal having a two-layered structureimmediately after manufacturing. The capsule for collecting anon-ferrous metal of the present invention having a two-layeredstructure shown in FIG. 1 (first embodiment) can be manufactured by anin-liquid dropwise addition method, for example, using a conventionallyknown capsule manufacturing apparatus provided with a concentric doublenozzle (10) shown in FIG. 3. Specifically, as shown in FIG. 3, thecapsule for collecting a non-ferrous metal having a two-layeredstructure can be manufactured by using a capsule manufacturing apparatusprovided with a concentric double nozzle (10) having a first nozzle(internal side) and a second nozzle (external side) to extrude an oilycomposition containing bacteria (11) being the capsule content throughthe internal first nozzle, and a shell formation composition (12)through the external second nozzle into a carrier fluid (16)simultaneously, and then curing the shell formation composition withlight irradiation.

In the method of manufacturing the capsule for collecting a non-ferrousmetal of the first embodiment, the oily composition containing bacteria(11) being the capsule content is injected through the internal firstnozzle, and the shell formation composition (12) is injected through theexternal second nozzle, via the concentric double nozzle (10). Then,upon contact between the capsule content and the shell formationcomposition in the carrier fluid (16), a seamless capsule of atwo-layered structure is constructed due to a difference betweenpolarity of the capsule content and polarity of the shell formationcomposition. More particularly, upon extrusion from the concentricdouble nozzle (1), a jet stream of a two-layered structure is formed dueto interface tension present between the carrier fluid (16) and theshell formation composition (12). Then, the jet stream forms sphericalliquid droplets having a two-layered structure by action of gravity.When forming liquid droplets, it is preferred that vibration is added tothe jet stream to make a particle size of the liquid droplet to beuniform. The carrier fluid (16) is circulated in the apparatus desirablyat a constant rate, by a driving means (17) such as a pump.

In addition, it is desirable that the carrier fluid (16) has differentpolarity from polarity of the shell formation composition. If the shellformation composition is hydrophilic (which is preferred), then thecarrier fluid (16) would preferably be hydrophobic, i.e. oily substance.Examples of the carrier fluid include olive oil, jojoba oil, corn oil,rapeseed oil, lard, beef tallow, whale oil, castor oil, soybean oil,rice oil, rice germ oil, coconut oil, palm oil, cacao oil, avocado oil,macadamia nut oil, squalane, mink oil, turtle oil, corn oil,hydrocarbons having 8 to 30 carbon atoms, beeswax, carnauba wax, ricewax, lanolin, liquid paraffin, vaseline, fatty acids having 4 to 30carbon atoms, esters of fatty acids having 4 to 30 carbon atoms andsucrose, esters of fatty acids having 4 to 30 carbon atoms and glycerol,aliphatic alcohols having 4 to 30 carbon atoms, esters of fatty acidshaving 4 to 30 carbon atoms and aliphatic alcohols having 4 to 30 carbonatoms, silicone oil and the like. The carrier fluid may be used solelyor in combination thereof. It is more preferred that the carrier fluidhas a viscosity of 10 to 300 mPa·s, and more preferably 30 to 200 mPa·sin the temperature range of 0° C. to 30° C.

The spherical liquid droplets having a two-layered structure are thenirradiated with light using a light source (14). The light irradiationmay be performed at any stage and, for example, the light irradiationmay be performed in the carrier fluid (16), or may be performed afterseparation of liquid droplets and the carrier fluid (16) via aseparation means (15) such as a net. Thus, the capsule for collecting anon-ferrous metal having a two-layered structure shown in a left drawingof FIG. 1 can be obtained.

The light source (14) is not particularly limited as far as it canradiate light having a wavelength of about 200 nm to about 800 nm andincludes, for example, a mercury lamp, a fluorescent lamp, a xenon lamp,a carbon arc lamp, and a metal halide lamp. The light source can beappropriately selected depending on a photocurable component used. Whena photosensitizer is blended with the shell formation composition, thephotocurable component can be cured by visible light. An irradiationtime can be set depending on an intensity of the light source or adistance from the light source. The irradiation time can generally be0.05 seconds to 10 minutes, preferably 0.1 seconds to 2 minutes.

The shell formation composition is cured by light irradiation to form ashell, thus obtaining capsules for collecting a non-ferrous metal. Theresulting capsules may be dried by a normal pressure drying method or areduced pressure drying method as necessary.

In the first embodiment (FIG. 1), since polarity of the capsule content(2) and polarity of the shell formation composition forming the shell(1) are different from each other, a capsule for collecting anon-ferrous metal can be simply produced. There is also an advantagethat a particle size distribution can be set narrow.

The obtained capsules of the present invention are immersed in asolution containing a non-ferrous metal, in which the solutioncontaining a non-ferrous metal permeates the shell and enters into thecapsules. A right drawing of FIG. 1 is a view showing the state where,after immersion, a solution containing a non-ferrous metal (5) permeatesa capsule, and the solution is present in the interior of the capsule.The bacteria and the solution in the capsule are brought into contactwith each other, and the bacteria are activated. Then, non-ferrous metalcollection activity by the bacteria is initiated, and a non-ferrousmetal is collected in the capsule.

The capsule for collecting a non-ferrous metal may be immersed in aliquid culture medium before immersion in a solution containing anon-ferrous metal, as necessary, to culture bacteria in the capsule. Forexample, the capsules of the present invention are immersed in a liquidculture medium such as TSB (Trypticase Soy Broth) at a pH of about 7 and30° C. for 6 to 72 hours, and number of bacterial in the capsules can beincreased by culturing.

Method of Manufacturing Capsule for Collecting Non-Ferrous Metal HavingThree-Layered Structure (Second Embodiment)

A left drawing of FIG. 2 is a schematic view showing a capsule forcollecting a non-ferrous metal having a three-layered structureimmediately after manufacturing. The capsule for collecting anon-ferrous metal of the present invention having a three-layeredstructure (second embodiment) shown in this FIG. 2 can be manufactured,for example, by an in-liquid dropwise addition method, using aconventionally known capsule manufacturing apparatus, in which theconcentric double nozzle is changed to a concentric triple nozzle, shownin FIG. 3. Specifically, the capsule for collecting a non-ferrous metalhaving a three-layered structure can be manufactured by using a capsulemanufacturing apparatus provided with a concentric triple nozzle havinga first nozzle (innermost portion), a second nozzle (intermediateportion) and a third nozzle (outermost portion) to extrude a hydrophiliccomposition containing Shewanella bacteria or the like through the firstnozzle, an oily composition through the second nozzle, and a shellformation composition through the third nozzle into a carrier fluid (16)simultaneously, and then curing the shell formation composition withlight irradiation. A specific procedure and the like in this method arethe same as those described above, with the exception that a concentrictriple nozzle is used in place of the concentric double nozzle.

In the capsule for collecting a non-ferrous metal obtained by themanufacturing method, an intermediate layer consisting of an oilysubstance (4) is present in the state of covering a hydrophiliccomposition (6) containing a bacterium of Shewanella bacteria or thelike, immediately after manufacturing. The presence of the intermediatelayer portion (4) makes it possible that the capsule content and theshell forming composition both have same polarity, for example, when thecapsule content is hydrophilic composition (6) containing Shewanellabacteria or the like, and a shell formation composition (1) can be samepolarity (hydrophilicity).

The obtained capsule having a three-layered structure may be broughtinto the state where the oily substance (4) is localized, as shown in aright drawing of FIG. 2, over time, by performing the aforementionedbacterium culturing treatment, or immersion in a solution containing anon-ferrous metal. Thereby, the bacteria and the solution in the capsuleare brought into contact with each other well, and the bacteria can beactivated well. Then, non-ferrous metal collection activity by thebacteria is initiated, and a non-ferrous metal is collected into thecapsule.

In the capsules having a three-layered structure, a composition obtainedby concentrating bacteria in a hydrophilic substance can be used as thecapsule content, as it is. Accordingly, the hydrophilic compositioncontaining bacteria can be prepared more easily. In addition, since ahydrophilic composition can be used as the capsule content, there isalso an advantage that an electron donating component and/or an electronaccepting component can be contained in the capsule content well.

The capsule of the present invention has a particle size of preferably0.1 to 10 mm, and more preferably 0.1 to 5 mm. The particle size of thecapsule of the present invention can be appropriately selected dependingon a kind and/or a concentration of a non-ferrous metal contained in asolution, a concentration of bacteria contained in the capsule, and thelike.

When the shell is formed using the shell formation compositioncontaining a thermosetting component, the capsule for collecting anon-ferrous metal can be manufactured by using a heated carrier fluid inplace of using the light source which radiates light, in theaforementioned manufacturing method.

In the case where the shell is formed from the shell formationcomposition containing a thermoplastic resin, the capsule for collectinga non-ferrous metal can be manufactured by using a cooled carrier fluidin place of using the light source which radiates light, in theaforementioned manufacturing method. In the case where the shellformation composition containing a thermoplastic resin is used, it ispreferable that a heating means is provided in a nozzle portion in acapsule manufacturing apparatus.

Method of Collecting Non-Ferrous Metal

According to the present invention, a non-ferrous metal can be collectedusing the capsule of the present invention. The method of collecting anon-ferrous metal in the present invention includes the following steps:

an immersion step of immersing the capsule for collecting a non-ferrousmetal in a solution containing a non-ferrous metal, and

a separation step of separating the capsule for collecting a non-ferrousmetal immersed in the immersion step.

The solution containing a non-ferrous metal, which can be used in themethod of the present invention, is not limited as far as it containsone or more of non-ferrous metals selected from the group consisting ofa rare metal and a rare noble metal. Examples of the solution include anon-ferrous metal-containing aqueous solution (percolate) prepared from:

a sea bottom mineral resource, such as cobalt-rich crust, manganesecrust, manganese nodule, and sea bottom hot water mineral deposit,

a marine mineral resource, such as sea water,

a land mineral resource, such as metal-containing oxidized mineral(e.g., laterite and monazite),

a waste component-containing recycle resource, such as metal-containingincineration residue obtained upon incineration of waste, and urbanmine, and the like.

It is preferable that the mineral component, such as a non-ferrous metalcontained in the solutions is crushed or ground in advance. When theparticle size of the mineral component is large, a specific surface areais small and thus a solid-liquid contact area is decreased, leading todeterioration in non-ferrous metal collection efficiency. In addition,when the particle size of the mineral component is larger as mentionedabove, the mineral component is easily precipitated, and thus there is apossibility that trouble is generated in an operation of collecting anon-ferrous metal.

According to the method of the present invention, the capsule forcollecting a non-ferrous metal is immersed in the solution containing anon-ferrous metal and a non-ferrous metal contained in the solutionpermeates the shell constituting the capsule. Thereby, a non-ferrousmetal is collected in the capsule.

If necessary, an electron donating component and/or electron acceptingcomponent may be added to a solution containing a non-ferrous metal. Byadding these components, an efficiency of collecting a non-ferrous metalmay be enhanced. For example, the electron donating component canpreferably be added to the solution containing a non-ferrous metal in aconcentration of 1 to 500 mM.

If necessary, the pH of the solution containing a non-ferrous metal maybe adjusted. It is more preferable that the solution containing anon-ferrous metal has a pH in the range of 6 to 9.

An immersion time for immersing the capsule for collecting a non-ferrousmetal in the solution containing a non-ferrous metal can beappropriately selected depending on a concentration of a non-ferrousmetal in the solution, and the like. The immersion time can generally be6 to 240 hours.

The capsules in which non-ferrous metal is collected by the immersionare separated from the solution. The separation operation herein has anadvantage that the capsule for collecting a non-ferrous metal can beseparated by a very simple operation, for example, filtration orsieving. The collected metal can be easily taken out by performingtreatment of destructing a capsule structure, or incineration treatmentof a capsule component under a temperature in such a range that does notadversely influence on the collected metal.

The capsule for collecting a non-ferrous metal of the present inventionhas an advantage that a non-ferrous metal can be easily collected by asimple operation of immersion in the solution containing a non-ferrousmetal for a given time. In this collection of a non-ferrous metal, thereis an advantage that, even in the case where an amount of a non-ferrousmetal contained is small, a non-ferrous metal can be concentrated andcollected effectively.

EXAMPLES

The present invention will be described in more detail by way of thefollowing Examples, but the present invention is not limited to them. InExamples, unless otherwise indicated, “part” and “%” are on a massbasis.

Example 1

Example 1 is a capsule for collecting a non-ferrous metal having atwo-layered structure immediately after manufacturing, in which acapsule content is an oily portion containing Shewanella bacteria, and ashell covering the capsule content is obtained by curing a shellformation composition containing a hydrophilic photocurable component.

The shell formation composition was prepared by mixing 60 parts by massof a 40% aqueous solution of ENTG-3800 (manufactured by Kansai PaintCo., Ltd.), 0.6 parts by mass of acetoin, and 20 parts by mass of a 0.5%aqueous poval solution.

The capsule content was prepared by dispersing and suspending Shewanellaoneidensis being reducing bacteria cultured at a high concentration incoconut oil being an oily substance, to prepare a suspension compositionin which a concentration was adjusted to 1.2×10⁸ cells/capsule per onecapsule.

Then, the capsules were obtained using an apparatus having a concentricdouble nozzle (a seamless capsule manufacturing apparatus, manufacturedby Morishita Jintan Co., Ltd.), shown in FIG. 3, in which the suspensioncomposition was injected through an internal nozzle of a double nozzle,and the shell formation composition was injected through an externalnozzle simultaneously into a carrier fluid flowing down to form capsuleparticles in the carrier fluid. Ultraviolet ray was radiated using ahigh pressure mercury lamp of a wavelength of 320 to 400 nm immediatelyafter formation of the capsule particles to polymerize the photocurablecomponent (ENTG-3800) of the shell formation composition, to obtainseamless capsules of a two-layered structure having a particle size of 4mm. Liquid paraffin was used as the carrier fluid.

Example 2

Example 2 is a capsule for collecting a non-ferrous metal having athree-layered structure immediately after manufacturing, in which acapsule content is a hydrophilic portion containing Shewanella bacteria,a shell covering the capsule content is obtained by curing a shellformation composition containing a hydrophilic photocurable component,and an intermediate layer is made of an oily substance.

The shell formation composition was prepared by mixing 60 parts by massof a 40% aqueous solution of ENTG-3800 (manufactured by Kansai PaintCo., Ltd.), 0.6 parts by mass of acetoin, and 20 parts by mass of a 0.5%aqueous poval solution.

The capsule content was prepared from a hydrophilic internal layercomposition in which a concentration of Shewanella oneidensis being areducing bacterium cultured at a high concentration was adjusted so thatthe bacterium was contained in a hydrophilic solution culture medium at1.2×10⁸ cells/capsule per one capsule.

The intermediate layer was prepared from an oily composition obtained bymixing sucrose acetate isobutyrate (SAIB) and coconut oil at a massratio of 50:50.

Then, the capsules were obtained using an apparatus in which aconcentric double nozzle was replaced with a concentric triple nozzle (aseamless capsule manufacturing apparatus, manufactured by MorishitaJintan Co., Ltd.) instead of the apparatus having the concentric doublenozzle shown in FIG. 3, in which the capsule content was injectedthrough an innermost nozzle of a triple nozzle, the intermediate layercomposition was injected through an middle nozzle, and the shellformation composition was injected through an outermost nozzlesimultaneously into an oily fluid flowing down to form capsule particlesin the oily fluid. Ultraviolet ray was radiated using a high pressuremercury lamp of a wavelength of 320 to 400 nm immediately afterformation of capsule particles to polymerize a photocurable component(ENTG-3800) of the shell formation composition, to obtain seamlesscapsules for collecting a non-ferrous metal of a three-layered structurehaving a particle size of 4 mm. Silicone oil was used as a carrierfluid.

Example 3

The seamless capsules for collecting a non-ferrous metal of atwo-layered structure obtained in Example 1 were immersed in a TSBliquid culture medium at a pH of 7.2 and 30° C. for 48 hours, andShewanella oneidensis contained in the capsules was cultured.

The cultured capsules were washed using a buffer solution (KH₂PO₄/NaOH).Then, the capsules were immersed in an aqueous solution (25° C., pH 7.0)containing 1 mM Pd (II) ion and 50 mM formic acid. Number of thecapsules immersed in the aqueous solution is 1.2×10⁷ capsules/m³.

Pd(II) ion concentrations were measured by an ICP (Inductively CoupledPlasma) light emission analyzing device at times of 3 minutes, 1 hour, 2hours, 3 hours, 4 hours, 5 hours and 24 hours passing after immersion ofthe capsules.

After 24 hours from the capsule immersion, the aqueous solutioncontaining the capsule was filtered, and the immersed capsules weretaken out.

In this experiment, the capsules were milky white after the culturingoperation and before immersion operation. On the other hand, thecapsules taken out after 24 hours from capsule immersion were gray toblack.

As comparative tests without using capsules, the aqueous solutioncontaining Pd (II) ion and formic acid obtained above was employedwithout adding anything (Comparative Example 1: control). The aqueoussolution containing Pd (II) ion and formic acid was mixed withShewanella oneidensis which was not encapsulated at a bacteriaconcentration of 6.7×10¹⁵ cells/m³ to suspend the cells (ComparativeExample 2). The aqueous solution containing Pd (II) ion and formic acidwas mixed with Shewanella oneidensis not encapsulated at a bacteriaconcentration of 6.7×10¹⁵ cells/m³ to suspend the cells and theconcentration of formic acid was adjusted to 200 mM (Comparative Example3). Pd (II) ion concentrations were measured at times of 3 minutes, 1hour, 2 hours, 3 hours, 4 hours, 5 hours and 24 hours passing after thebacteria were put in, using an ICP light emission analyzing device.

A graph showing changes in Pd (II) ion concentration in the aqueoussolution in Example 3 and these comparative tests is shown in FIG. 4.

In two comparative tests in which Shewanella oneidensis was added as itis to suspend the cells, measurement was stopped because Pd (II) ionconcentration after 2 hours was considerably decreased.

Example 4

The seamless capsules for collecting a non-ferrous metal of atwo-layered structure obtained in Example 1 were immersed in a TSBliquid culture medium at a pH of 7.2 and 30° C. for 48 hours, and S.oneidensis contained in the capsule was cultured.

The cultured capsules were washed with a buffer solution (KH₂PO₄/NaOH).Then, the capsules were immersed in an aqueous solution (25° C., pH 7.0)containing 5 mM Pd(II) ion and 200 mM formic acid. Number of capsulesimmersed in the aqueous solution was 1.2×10⁷ capsules/m³.

After 24 hours from the capsule immersion, the aqueous solutioncontaining the capsules was filtered, and the immersed capsules weretaken out.

In this experiment, the capsules after the culturing operation andbefore immersion operation were milky white. On the other hand, thecapsules taken out after 24 hours from capsule immersion were black.

Photographs of the capsules before immersion operation (after culturingoperation, before immersion experimental operation, left), and thecapsules taken out after 24 hours from capsule immersion (right) areshown in FIG. 5.

As shown in Example 3, the concentration of a palladium ion in theaqueous solution could be significantly reduced by immersing thecapsules for collecting a non-ferrous metal of the present invention inthe aqueous solution containing a palladium ion for 24 hours. Thecapsules after immersion were gray to black, and the capsules could beeasily taken out by filtration.

In the comparative test in which Shewanella oneidensis was added as itis to the aqueous solution containing a palladium ion at a concentrationof 6.7×10¹⁵ cells/m³ to suspend the cells, palladium ion in the aqueoussolution was significantly reduced at time of 2 hours. However, in thisexperimental example, it was difficult to take out the bacteria byfiltration or the like, because Shewanella oneidensis was dispersed inthe suspended state.

Example 5

The capsules for collecting a non-ferrous metal having a three-layeredstructure immediately after manufacturing obtained in Example 2 wereimmersed in a TSB liquid culture medium at a pH of 7.2 and 30 degreesfor 48 hours as in Examples 3 and 4, and bacteria contained in thecapsule were cultured.

The cultured capsules were washed using a buffer solution (KH₂PO₄/NaOH).Then, the resulting capsules were immersed in an aqueous solution (pH3.5, 20 mL) having an indium chloride concentration of 1 mM. Number ofthe capsules which were immersed in the aqueous solution was 100. Numberof bacteria present in the capsules immersed in the aqueous solution was1.0×10¹⁰ cells/ml.

The concentrations of an indium ion contained in the aqueous solutionwere measured using an ICP light emission analyzing device at a timebefore capsule immersion, and at times of 5 minutes, 30 minutes, 1 hour,2 hours, 3 hours and 6 hours after capsule immersion. The collectionrate of indium at the time after 6 hours from capsule immersion was98.5%.

In addition, as a comparative test, also regarding the aqueous solutionin which the capsule was not immersed, the indium ion concentration wasmeasured at each of the aforementioned times.

A graph showing changes in indium ion concentration in the aqueoussolution in Example 5 and the comparative test is shown in FIG. 6.

Example 6

Example 6 shows that gold was recovered from wastes of IC chips.Capsules having a three-layered structure immediately aftermanufacturing were prepared as follow.

A shell formation composition was prepared by mixing 60 parts by mass ofa 40% aqueous solution of RM-6572 (manufactured by Sanyu Rec Co., Ltd.),0.6 parts by mass of acetoin, and 20 parts by mass of a 0.5% aqueouspoval solution.

A hydrophilic internal layer composition was prepared as a capsulecontent by mixing Shewanella algae being a reducing bacterium culturedat a high concentration in a hydrophilic solution culture medium so thatthe bacteria was contained at 1.2×10⁸ cells/capsule per one capsule.

An oily composition was prepared as an intermediate layer composition bymixing sucrose acetate isobutyrate (SAIB) and coconut oil at a massratio of 50:50.

Then, capsules were obtained using an apparatus in which a concentricdouble nozzle was replaced with a concentric triple nozzle (seamlesscapsule manufacturing apparatus, manufactured by Morishita Jintan Co.,Ltd.) instead of the apparatus having a concentric double nozzle shownin FIG. 3, wherein the capsule content was injected through an innermostnozzle of a triple nozzle, the intermediate layer composition wasinjected through an intermediate nozzle, and the shell formationcomposition was injected through an outermost nozzle simultaneously intoan oily fluid flowing down to form capsule particles in the oily fluid.Ultraviolet ray was radiated on the capsule particles using a highpressure mercury lamp of a wavelength of 320 to 400 nm immediately afterformation of capsule particles to polymerize a photocurable component(RM-6572) of the shell formation composition, to obtain seamlesscapsules for collecting a non-ferrous metal of a three-layered structurehaving a particle size of 4 mm. Silicone oil was used as a carrierfluid.

The capsules for collecting a non-ferrous metal having a three-layeredstructure, thus obtained, were immersed in a TSB liquid culture mediumat a pH of 7.2 and 30 degrees for 48 hours as in Examples 3 and 4, andthe bacteria contained in the capsule were cultured.

The cultured capsules was washed using a buffer solution (KH₂PO₄/NaOH).

Wasted IC (semiconductor integrated circuit) chips were finely ground toobtain an IC chip ground product. The resulting IC chip ground productwas immersed for 1 day in an aqueous solution, a pH of which had beenadjusted to 0.7 using hydrochloric acid, to prepare an IC chippercolate.

The capsules obtained above were immersed in the obtained IC chippercolate (pH 0.7, 20 mL). Number of the capsules that were immersed inthe IC chip percolate was 100. Number of the bacteria present in thecapsule immersed in the IC chip percolate was 3.0×10¹⁰ cells/ml.

Concentrations of gold element contained in the IC chip percolate weremeasured using an ICP light emission analyzing device at a time beforecapsule immersion and at times of 10 minutes, 30 minutes, 1 hour, 2hours, 3 hours and 6 hours after capsule immersion. A collection rate ofgold after 6 hours from capsule immersion in Example 6 was 75.7%.

As comparative experiments without capsules, the IC chip percolate wasemployed as it is without bacteria. Separately, Shewanella algae wasadded to the IC chip percolate at a concentration of 4.0×10¹⁰ cells/mlto suspend the cells. Concentration of gold ion was measured at each ofthe aforementioned times using an ICP light emission analyzing device.

A graph showing changes in concentration of gold ion ([AuCl₄]⁻) in theIC chip percolate in Example 6 and the comparative tests is shown inFIG. 7.

From the Examples 5 and 6, it was confirmed that indium and gold couldbe collected using the capsules for collecting a non-ferrous metal ofthe present invention.

Further, as shown in Example 6, it was also confirmed that gold could berecovered from the wasted IC chips. The IC chip percolate used inExample 6 is a strong acidic aqueous solution having a pH of 0.7. It wasconfirmed that gold could be recovered well from the strong acidicaqueous solution.

In addition, also in the comparative test of Example 6, in whichShewanella algae was added as it is to the IC chip percolate at aconcentration of 4.0×10¹⁰ cells/ml to suspend the cells, concentrationof gold ion was significantly reduced. However, in Example 6, it wasdifficult to take out the bacterial by filtration or the like, becauseShewanella algae was dispersed as they were in the suspension state.

In addition, Example 6 shows that the capsules for collecting anon-ferrous metal of the present invention can selectively collect onlygold, from an IC chip percolate although the IC chip percolate containsa variety of metal other than gold as collection subject metal. The ICchip percolate contains a variety of metal components such as copperother than gold. It was confirmed that the concentration of copper ioncontained in the IC chip percolate used in Example 6 is as high as theconcentration of gold ion. Nevertheless, a metal component collected inthe capsules for collecting a non-ferrous metal was only gold in Example6. Thus, it was confirmed that the capsules for collecting a non-ferrousmetal of the present invention had extremely excellent performance thatonly gold could be selectively collected from the IC chip percolatecontaining gold and copper.

Example 7

The capsules for collecting a non-ferrous metal having a three-layeredstructure immediately after manufacturing, manufactured in Example 6,were subjected to the culturing operation as explained in Example 6.

The resulting capsules were immersed in an aqueous solution (pH 7.0, 20mL) containing 1 mM platinum (IV) ion and 50 mM sodium lactate. Numberof the capsules immersed in the aqueous solution was 100. Number of thebacteria present in the capsule immersed in the aqueous solution was3.0×10¹⁰ cells/ml.

Concentrations of platinum contained in an aqueous solution weremeasured using an ICP light emission spectral analysis device at a timebefore capsule immersion, and at times of 10 minutes, 30 minutes, 1hour, 3 hours, and 6 hours after capsule immersion. A collection rate ofplatinum after 6 hours from capsule immersion in Example 7 was 72.0%.

In addition, as a comparative test, the aqueous solution was employed asit was without the capsules and a platinum concentration was measured ateach of the aforementioned times.

A graph showing changes in platinum (IV) concentration in the aqueoussolution in Example 7 and this comparative test is shown in FIG. 8.

Example 8

According to the same manner as that of Example 6 except that, as theshell formation composition forming a shell, a composition in which 60parts by mass of a 40% aqueous solution of UA-7100 (manufactured byShin-Nakamura Chemical Co., Ltd.), 0.6 parts by mass of acetoin, and 20parts by mass of a 0.5% aqueous poval solution were mixed, was preparedand used, capsules for collecting a non-ferrous metal having athree-layered structure immediately after manufacturing was obtained.Then, the resulting capsules were subjected to the culturing operationas explained in Example 6.

The capsules thus obtained were immersed in an aqueous solution (pH 3.6,20 mL) containing 1 mM gallium (III) ion. Number of the capsulesimmersed in the aqueous solution was 100. Number of the bacteria presentin the capsules immersed in the aqueous solution was 3.0×10¹⁰ cells/ml.

Concentrations of gallium contained in the aqueous solution weremeasured using an ICP light emission spectral analysis device at a timebefore capsule immersion, and at time of 15 minutes, 30 minutes, 1 hour,3 hours, and 6 hours after capsule immersion. A collection rate ofgallium after 6 hours from capsule immersion in Example 8 was 79.2%.

In addition, as a comparative test, the aqueous solution containinggallium ion was employed as it was without the capsules, and a galliumconcentration was measured at each of the aforementioned times.

A graph showing changes in gallium (III) ion concentration in theaqueous solution in Example 8 and this comparative test is shown in FIG.9.

Example 9

The capsules for collecting a non-ferrous metal having a three-layeredstructure immediately after manufacturing, manufactured in Example 6were subjected to the culturing operation as explained in Example 6.

The resulting capsules were immersed in an aqueous solution (pH 7.0, 20mL) containing 1 mM rhodium (III) ion and 50 mM sodium formate. Numberof the capsules immersed in the aqueous solution was 100. Number of thebacteria present in the capsule immersed in the aqueous solution was3.0×10¹⁰ cells/ml.

Concentrations of rhodium contained in the aqueous solution weremeasured using an ICP light emission spectral analysis device a timebefore capsule immersion, and at times of 10 minutes, 30 minutes, 1hour, 3 hours, and 6 hours after capsule immersion. A collection rate ofrhodium after 6 hours from capsule immersion in Example 9 was 58.0%.

In addition, as a comparative test, the aqueous solution was employed asit was without the capsules and a rhodium concentration was measured ateach of the aforementioned times.

A graph showing changes in rhodium (III) ion concentration in theaqueous solution in Example 9 and this comparative test is shown in FIG.10.

Example 10

The capsules for collecting a non-ferrous metal having a three-layeredstructure immediately after manufacturing, manufactured in Example 6were subjected to the culturing operation as in Example 6.

The resulting capsules were immersed in an aqueous solution (pH 5.5, 20mL) containing 0.5 mM dysprosium (III) ion. Number of the capsulesimmersed in the aqueous solution was 100. Number of the bacteria presentin the capsule immersed in the aqueous solution was 3.0×10¹⁰ cells/ml.

Concentrations of dysprosium contained in the aqueous solution weremeasured using an ICP light emission spectral analysis device at a timebefore capsule immersion, and at times of 15 minutes, 30 minutes, 1hour, 3 hours, and 6 hours after capsule immersion. A collection rate ofrhodium after 6 hours from capsule immersion in Example 10 was 88.0%.

In addition, as a comparative test, the aqueous solution was employedwithout the capsules, and a dysprosium concentration was measured ateach of the aforementioned times.

A graph showing changes in dysprosium (III) ion concentration in theaqueous solution in Example 9 and this comparative test is shown in FIG.11.

As shown in Examples 7 to 10, it was confirmed that a variety ofnon-ferrous metals such as platinum, gallium, rhodium and a rare earthelement could be collected using the capsules for collecting anon-ferrous metal of the present invention.

In Examples, a collection rate and/or a collection speed of anon-ferrous metal can be improved by a method, e.g. (1) an increase ofnumber of bacteria contained in the capsule for collecting a non-ferrousmetal, (2) an increase of number of capsules for collecting anon-ferrous metal to be immersed in the aqueous solution, and (3) adesign change of a particle size of the capsule for collecting anon-ferrous metal to a range of 0.1 to 2 mm.

INDUSTRIAL APPLICABILITY

The capsule for collecting a non-ferrous metal of the present inventionhas an advantage that, by a simple operation of immersion in a solutioncontaining a non-ferrous metal for a given time, a non-ferrous metal canbe easily collected. In collection of a non-ferrous metal using thecapsule for collecting a non-ferrous metal of the present invention, anon-ferrous metal can be collected without accompanying consumption of alarge amount of energy like a method using a chemical reaction. There isan advantage that a large amount of waste solvent like a solventextraction method is not accompanied, and the load on the environment isalso small. Further, in the present invention, since a non-ferrous metalcan be collected by a simple operation of immersing a capsule forcollecting a non-ferrous metal in a solution for a given period and,thereafter, taking out the capsule by a means such as filtration, thereis an advantage that implementation is simple without accompanying thelarge cost of facility investment.

EXPLANATION OF NUMBERS IN DRAWINGS

-   1: Shell,-   2: Oily portion,-   3: Capsule content,-   4: Intermediate layer portion (oily substance),-   5: Hydrophilic portion,-   6: Hydrophilic portion,-   10: Double nozzle,-   11: Capsule content,-   12: Shell formation composition,-   13: Formation tube,-   14: Light source,-   15: Separation means,-   16: Carrier fluid,-   17: Driving means.

1. A capsule for collecting a non-ferrous metal comprising a capsulecontent and a shell covering the capsule content, wherein the capsule isimmersed in a solution containing the non-ferrous metal to collect thenon-ferrous metal in the capsule.
 2. The capsule for collecting anon-ferrous metal according to claim 1, wherein the capsule contentcomprises one or more bacteria selected from the group consisting ofGeobacter bacteria, Desulfomonas bacteria, Desulfuromusa bacteria,Pelobacter bacteria, Shewanella bacteria, Ferrimonas bacteria, Aeromonasbacteria, Sulfurospirillum bacteria, Wolinella bacteria, Desulfovibriobacteria, Geothrix bacteria, Deferribacter bacteria, Geovibrio bacteria,Pyrobaculum bacteria, Thermotogae bacteria, Archaeoglobus bacteria,Pyrococcus bacteria and Pyrodictium bacteria.
 3. The capsule forcollecting a non-ferrous metal according to claim 1, wherein the capsulecontent comprises Shewanella bacteria.
 4. The capsule for collecting anon-ferrous metal according to claim 1, wherein the capsule contentcomprises Shewanella oneidensis or Shewanella algae.
 5. The capsule forcollecting a non-ferrous metal according to claim 1, wherein thenon-ferrous metal to be collected is one or more selected from the groupconsisting of a rare metal and a rare noble metal.
 6. The capsule forcollecting a non-ferrous metal according to claim 1, wherein thenon-ferrous metal to be collected is palladium, platinum, rhodium, gold,silver, indium, gallium or a rare earth element.
 7. The capsule forcollecting a non-ferrous metal according to claim 1, wherein the capsulecontent further comprises at least one selected from the groupconsisting of an electron donating component, an electron acceptingcomponent and a liquid culture medium.
 8. The capsule for collecting anon-ferrous metal according to claim 1, wherein the capsule forcollecting a non-ferrous metal is a seamless capsule.
 9. The capsule forcollecting a non-ferrous metal according to claim 1, wherein the shellis obtained by curing a shell formation composition comprising aphotocurable component and a shell permeation aid.
 10. The capsule forcollecting a non-ferrous metal according to claim 9, wherein thephotocurable component is one or more selected from the group consistingof an acrylate-based oligomer, an unsaturated polyester-based oligomer,an polyene thiol-based oligomer, a cinnamic acid-based oligomer, anepoxy-based oligomer, a vinyl ether-based oligomer and an unsaturatedpolyamide-based oligomer, and the shell permeation aid is one or moreselected from the group consisting of alginic acid, polyvinyl alcohol,agar, carrageenan, gellan gum, pectin, starch, a starch derivative,dextrin, cellulose and protein.
 11. The capsule for collecting anon-ferrous metal according to claim 1, wherein the capsule contentcomprises an oil containing Shewanella bacteria.
 12. The capsule forcollecting a non-ferrous metal according to claim 1, wherein the capsulecontent comprises an intermediate layer portion containing an oilysubstance, and a hydrophilic portion containing Shewanella bacteria,wherein the intermediate layer portion is in layer structure at the timeof preparing a capsule.
 13. The capsule for collecting a non-ferrousmetal according to claim 11, obtained by: extruding an oily compositioncomprising Shewanella bacteria from a first nozzle, and extruding ashell formation composition from a second nozzle simultaneously into acarrier fluid, wherein the first nozzle and the second nozzle areconcentrically arranged with sequentially increased radiuses in whichthe first nozzle is present innermost and the second nozzle is presentoutermost, and then, curing the shell formation composition with lightirradiation.
 14. The capsule for collecting a non-ferrous metalaccording to claim 12, obtained by: extruding a hydrophilic compositioncomprising Shewanella bacteria from a first nozzle, extruding an oilycomposition from a second nozzle and extruding a shell formationcomposition from a third nozzle simultaneously into a carrier fluid,wherein the first nozzle, the second nozzle and the third nozzle areconcentrically arranged with sequentially increased radiuses in whichthe first nozzle is present innermost and the third nozzle is presentoutermost, and then curing the shell formation composition with lightirradiation.
 15. A method of collecting a non-ferrous metal, comprising:an immersion step of immersing the capsule for collecting a non-ferrousmetal according to claim 1 in a solution containing a non-ferrous metal,and a separation step of separating the capsule for collecting anon-ferrous metal immersed in the immersing step.
 16. The method ofcollecting a non-ferrous metal according to claim 15, wherein thenon-ferrous metal to be collected is one or more selected from the groupconsisting of a rare metal and a rare noble metal.
 17. The method ofcollecting a non-ferrous metal according to claim 15, wherein thenon-ferrous metal to be collected is palladium, platinum, rhodium, gold,silver, indium, gallium or a rare earth element.